Apparatus for discharging contents of a sealed container

ABSTRACT

An apparatus for discharging the contents of a sealed container, such as a test tube, includes an inlet path and a discharge path with a delivery tube in the discharge path. A predetermined clearance is provided between the exterior of the delivery tube and the interior of the discharge path, the clearance providing venting, or blow-by, such that temperature changes do not cause accidental discharge of the contents of the container, while still maintaining sufficient resistance to venting for permitting pressurizing the interior of the test tube for accurately controlling the discharge of the test tube contents.

CROSS REFERENCE TO RELATED APPLICATION

Some of the subject matter disclosed in the present application iscommon to the earlier application of Tipton Golias, application No.07/208,447, filed June 20th, 1988 and assigned to the Assignee of thepresent invention.

BACKGROUND OF THE INVENTION

The present invention relates generally to an apparatus for dischargingthe contents of a sealed container and has particular utility indischarging the contents of a test tube, serum collection tube or thelike.

Test tubes are frequently used as collection containers for bloodspecimens and the like. Typically, an anticoagulant is placed in thetest tube, then a blood specimen is withdrawn from a patient and placedinto the test tube, and then the test tube sealed with a resilientclosure or stopper which is typically formed of rubber. The test tubeand its contents are thereafter subjected to temperature variations aswell as centrifuging operations. Prior to the invention described in theaforementioned co-pending application, after centrifuging, it wastypical to remove the stopper from the test tube such that some of thecontents could be transferred to a specimen plate or the like foranalysis.

There were, of course, numerous problems associated with the removal ofthe stopper from the test tube such as the potential for contaminationof the blood and exposure of the laboratory technician to any diseasescarried by the blood. Of course, there is substantial present concern bythe laboratory technician because of potential exposure to the HIVvirus, hepatitis or other diseases which may be carried by the blood.The prior application describes a first solution to the aforementionedproblem by the provision of a method and apparatus for discharging thecontents of a sealed container which includes, in general terms, aholder containing two cannulas, or needles, which are utilized topuncture the rubber stopper or closure of the test tube. One of thecannulas is connected to a compressible bulb or pump, and delivery tubeis inserted through the second cannula into the interior of the testtube. Then, upon compressing the bulb, air is introduced into the testtube and the contents of the test tube are pressurized and thus,partially discharged through the delivery tube onto a specimen plate.

Prior to the present invention, however, several further concerns becameapparent. Once concern was the degree of force required on the pump orbulb mechanism in order to cause one or more droplets to be discharged.Thus, the laboratory technician desired the ability to actuate the pumponly once and, in response a single droplet would be discharged. But itwas also required that air be able to enter the interior of the sealedtest tube after the droplet was discharged for two reasons, namely,first, to avoid creating a reduction in pressure or partial vacuumwithin the test tube and second, to fill the compressible bulb so that asecond droplet could be discharged.

Yet a second problem arose because collection tubes of the typeheretofore described frequently undergo temperature changes in excess of30° C. For example, a sealed collection tube containing blood isfrequently refrigerated, tending to cause a pressure decrease within thecollection tube. Also, in a laboratory, the collection tube may increaseto room temperature or, if positioned in direct sunlight, to an evengreater temperature, thus tending to cause a pressure increase and evenan accidental discharge of the test tube contents.

SUMMARY OF THE INVENTION

We have discovered that it is necessary to provide some clearance, orventing, between the interior and exterior of the sealed test tube.Preferably the venting is between the outside diameter of the deliverytube and the interior of the cannula, or conduit, through which thedelivery tube is positioned. Then, of course, as the test tube undergoestemperature changes, air can be drawn into or expelled out of theinterior of the test tube. However, the clearance cannot be large,otherwise in response to compressing the bulb or pump, too much airwould pass through this clearance, thus reducing the pumping efficiency.In fact, if the clearance was excessive, then no fluid would bedischarged. This phenomenon is referred to as "blow-by". If theclearance is larger than necessary, then repeated pumping and/orexcessive force is required on the pump in order to discharge fluid fromthe test tube through the delivery tube to a specimen plate. Hence, itis necessary to minimize the clearance, thus yielding a discharge ordelivery system which is extremely responsive to the pressure on thepump mechanism.

Yet another consideration which has developed subsequent to theinvention described in the prior application is a desire to facilitateinsertion of the apparatus into the rubber closure or stopper of thetest tube. We have discovered that while the prior approach isfunctional, a new and improved approach provides additional benefits aswill be described.

The present invention provides an improved apparatus for discharging thecontents of a sealed test tube which permits better control of the rateand amount of discharge, accommodates changes in temperature of the testtube and its contents and also provides for easier insertion of theapparatus through the resilient rubber closure, or stopper, of the testtube.

BRIEF DESCRIPTION OF THE DRAWINGS

The various features, objects and benefits of the present invention,together with additional benefits which will be attained by its use,will become more apparent upon reading the following detaileddescription of the invention taken in connection with the drawings.

In the drawings, wherein like reference numerals identify correspondingcomponents:

FIG. 1 is an exploded illustration, partly in section, of a portion of atest tube, a test tube stopper and the apparatus of the presentinvention;

FIG. 2 is an illustration, partly in section, of a second form of theapparatus of the present invention;

FIG. 3 is bottom view of the apparatus of FIG. 2;

FIG. 4 is a partial, sectional illustration of a preferred embodiment ofthe present invention;

FIG. 5 is a sectional view as seen in the direction of arrows 5--5 ofFIG. 4; and

FIG. 6 is a partial elevation view of an alternate embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

With reference to the drawings, and more particularly FIG. 1, acontainer 10 is partially illustrated and should be understood to referto a conventional test tube, serum collection tube or the like. Thus,the container 10, which will be referred to as a test tube, is formed asan elongated member with a hollow interior having a thin wall, an openfirst end 12 and typically a closed, rounded second end, or bottom (notshown). A test tube of this nature is typically circular in crosssection although other cross sectional configurations may be utilized.

The test tube 10 has its end 12 closed by a resilient, self-sealing,reusable closure, or stopper, 14 which would also be of circular crosssection (in plan view), having an enlarged head 16 and a stem 18 suchthat the stopper is of generally "T" shape in cross section. The stopperis configured to frictionally resiliently sealingly engage the interiorof the wall of the test tube 10 at the end 12, as well as engage thetest tube rim, as is conventional. Also, as is conventional, the topcentral portion of the stopper head may include a slight concavity, orrecess, 20.

Means are provided for discharging the contents of the sealed test tube10 without removing the stopper 14, and means are provided forestablishing a fluid inlet path and a fluid discharge path. The twofluid paths are established by puncturing the stopper 14, and then byconnecting a pump to one end of the input path, the interior of the testtube may be slightly pressurized to cause fluid to flow through thedischarge path. In the embodiment of FIG. 1, means 24 is provided forestablishing a fluid inlet path and a fluid discharge path including abody member 26 having two bores therethrough. Each bore is fitted with ahollow needle, or cannula, 28, 30, respectively, and each cannula has atapered, or sharpened, end positioned to puncture, or pierce, the head16 of the stopper 14 as the body 26 is moved toward the stopper 14.

A delivery tube, or the like, 32 is inserted through the needle 30, andthe delivery tube is slidable within the needle 30 such that afterneedles 28 and 30 penetrate through, or pierce, the stopper, a deliverytube 32 may be inserted into the needle 30 and moved into the fluid 34.

A pump means 36 is connected to the needle 28 such that upon actuatingthe pump means, air is introduced through the interior of the needle 28to slightly pressurize the interior of the test tube, thus forcing adroplet of fluid 34 to be forced through the delivery tube 32 to thus bedischarged onto a specimen plate or the like. The tube 32 may beextended into the fluid 34 to a desired depth to access different levelsof fluid within the tube. The pump means 36 which is provided at one endof the needle 28, may be a bellows, as illustrated, or other form ofresiliently compressible bulbous member.

At one end of the body member 26, preferably the end opposite thesharpened points of the needles, a plurality of barbs 38, of generallycircular cross section, are provided for securing the pump means, orbellows, 36 to the body.

According to the principles of the present invention, we have discoveredthat a certain clearance is necessary between the outside or exteriordiameter of the delivery tube 32 and the interior of the needle 30. Inthe embodiment of FIG. 1, the needles are hollow and of circular crosssection and the delivery tube is hollow and of circular cross section.According to the principles of the present invention, if the interiordiameter of the discharge path, or needle 30, is 0.045 inches, then theoptimum, outside diameter of the deliver tube 32 should be 0.044 inches.Thus, the clearance would be 0.001 inches, in diameter. The crosssectional clearance area may be calculated as ##EQU1## where D₂ =0.045inches and D₁ =0.044 inches.

While this appears to be an optimal clearance, satisfactory results havebeen obtained with a sightly larger clearance, as well as with aslightly smaller clearance. However, as the clearance increases, thereis a loss of the ability to pressurize the interior of the test tube.Stated alternatively, there is excessive leakage of air in responseactuation of the pump means, and, as a consequence, additional pressureis required to discharge fluid. This additional pressure may be suppliedby either applying greater force to the pump means or by repeatedlyactivating the pump means, but in either event, there is a reduction inthe ability to control the fluid discharge. Also, as the clearancedecreases, there is insufficient venting as the test tube with fluidtherein is subjected to temperature differnetials. Thus, it is importantto balance these considerations to provide venting while maintaining theability to pressurize the test tube.

Referring next to FIGS. 2 and 3, an alternate form of the presentinvention will now be described. The means 24 for establishing the firstand second fluid flowpaths, or the inlet and discharge paths, within thestopper 14 of test tube is illustrated as including an elongated bodymember 40 being of circular configuration at one end to which the pumpmeans, or bellows, 36 is attached. The body member has two circularbores 42, 44, respectively, therethrough corresponding to the bores ofthe needles 28 and 30 in the embodiment of FIG. 1. Hence, the two bores42, 44 extend through the length of the body 40, and are generallyparallel to each other and parallel to the elongated axis of the body.The exterior diameter and configuration of the body changes from a firstend 46 where the bellows is attached toward the second end or tip 48.Specifically, the cross section is circular but approximately at the midpoint 50 along the length of the body, the cross sectional configurationbecomes generally flat and blade-like, with curved sides 51, 52. Thus,the body member 40 of FIGS. 2 and 3 may be considered as aself-contained spike for piercing the rubber stopper of the test tube.By locating the pointed tip 48 generally centered between the lateralextremities of the body (e.g., as seen from the bottom), the body member40 will self-center as it is inserted through the rubber stopper 14. Thebellows, or pump, is attached to one end of one bore 42, which functionsas the input bore and a delivery tube 32 is inserted through thedischarge bore 44. Hence, the diameter of the discharge bore 44 shouldbe slightly greater than the outside diameter of a delivery tube 32, tothus provide the desired clearance.

Referring next to FIGS. 4 and 5, a preferred embodiment of the presentinvention is illustrated, including means 60 for puncturing the stopperand for establishing the fluid inlet path and the fluid discharge path.The means 60 for establishing the fluid flow paths is an elongated spikehaving a head 62 of circular cross section, and the cross sectionthereafter gradually tapering to a thin, flat blade-like portion 64culminating in a puncturing tip 66 at the end opposite the head 62.Barbs 38 are provided to facilitate securing a pump means to the body60. A bore 68 of circular cross section is provided through the spikewith one end of the bore 68 extending through the barbs 38 to which thebellows is secured, and the opposite end 70 of the bore being positionedadjacent the pointed tip 66. The tip is centered, laterally to providefor self-centering of the spike as it is inserted into the stopper. Asecond, straight bore 72 is provided in the body at an angle relative tothe bore 68, the bore 72 having one end 74 opening into the head 62 ofthe spike, and the opposite end 76 intersecting the bore 68.

In the embodiment of FIGS. 4 and 5, the delivery tube 32 is insertedthrough the bore 72, and thereafter, where the bore 72 intersects thebore 68 as at 76, the delivery tube 32 extends through the bore 68beyond the bore end 70 and beyond the tip 66 into the fluid within thetest tube. Thus, the bore 68 must be sufficiently large, in diameter, toaccommodate the diameter of the delivery tube 32 and to allow air to beintroduced into the interior of the test tube 10 in response to pressureon the bellows, or pump means, 36. In addition, there must be a ventingclearance between the outside diameter of the delivery tube 32 and theinside diameter of the discharge path along the entire length of thebore 72, and along bore 68 from its intersection 76 to the bore end 70.The embodiment of FIG. 4, when compared to the embodiment of FIG. 2,provides a second bore 72 in FIG. 4 which is relatively short in length,thus permitting a smaller thickness blade portion 64 as well as beingeasier to manufacture. In the embodiment of FIG. 4, a portion of theinlet and outlet paths may be considered co-extensive and with thedelivery tube properly inserted, a portion of the inlet and outlet pathsare concentric.

The generally squared-off mid-point 50 of the body member 40 of FIG. 2and the corresponding portion of the member 60 of FIG. 4 provide anadditional benefit. During manufacture of the apparatus of the presentinvention, the spikes 48, 66 or pointed, sharpened cannulas 28, 30 maybe inserted into a material such as Styrofoam, which is a Dow ChemicalCompany trademark for an expanded rigid polystyrene, for protection. Thesquared-off mid-points limit the depth of the insertion into theStyrofoam. When a plurality of body members are aligned in a row withina Styrofoam block, the feature of inserting all the body members to thesame depth enables the entire row of body members to be loaded into aninsertion machine for automatically inserting the puncturing mechanismsinto test tubes. Hence, the squared-off mid-points function as a locatorfor subsequent insertion of the puncturing mechanism.

Referring now to FIG. 6, yet another embodiment of the present inventionis illustrated wherein means 80 for establishing the fluid paths isgenerally similar to the embodiment of FIGS. 4 and 5. One difference,however, is that on the exterior of the blade-like portion 64, there area plurality of serrations, teeth or barbs 82. Hence, upon insertion ofthe spike means 80 through the stopper, these teeth tend to resist anytendency to accidentally withdraw the spike means from the test tubestopper. A second distinction between the embodiment of FIG. 4 and theembodiment of FIG. 6 is that in the embodiment of FIG. 6, the outletpath bore is curved, or arcuate, as at 84 rather than a straight bore 72as illustrated in FIG. 4, from the head of the spike to the intersectionwith a main bore 68. However, a common aspect of the embodiments ofFIGS. 4 and 6 is that a portion of the inlet path and a portion of thedischarge path are concentric whereas in the embodiments of FIGS. 1 and2, the inlet path and discharge path are non-concentric.

Each of the puncturing means of FIGS. 2-6 provides a sharpened tip fornot only piercing but also for self-centering relative to the stopper.This is an advantage over the configuration of FIG. 1 in that only asingle puncture is made in the stopper.

The bellows, or pump means, is preferably a low density polyethylenewhile the body member is preferably a impact stryene. In the embodimentof FIG. 1 the needles are metal. The delivery tube may be Teflon, whichis a DuPont trademark for a polytetrafluoroethylene.

The foregoing is a complete description of the present invention.Various changes may be made without departing from the spirit and scopeof the present invention and thus, it should be appreciated that thepresent invention has been illustrated and described with numerousembodiments. The invention, therefore, should be limited only by thescope of the following claims.

What is claimed is:
 1. Apparatus for transferring fluid from a testtube, the test tube having a resilient self-sealing, reusable,repuncturable closure at one end, said apparatus comprising means forpuncturing said resilient, self-sealing, reusable closure and forestablishing a fluid inlet path and a fluid discharge path, said fluiddischarge path having an inside diameter;delivery means extendingthrough said discharge a clearance being defined as the region betweenthe outer diameter of the delivery means and the inside diameter of saidfluid discharge path; and means for pressurizing the interior of thetest tube for discharging fluid through said delivery means; saidclearance for venting of the interior of the test tube in response totemperature variations and for maintaining the ability to pressurize theinterior of the test tube.
 2. The invention as defined in claim 1wherein said apparatus is self-centering relative to the test tubeclosure when said apparatus punctures said closure.
 3. The invention asdefined in claim 1 wherein said apparatus includes means for piercingsaid test tube closure in more than one location.
 4. The invention asdefined in claim 1 wherein said delivery means includes a delivery tubeextending through said discharge path.
 5. The invention as defined inclaim 1 wherein said means for establishing said fluid paths has aplurality of discrete bores therethrough.
 6. The invention as defined inclaim 1 wherein said means for establishing said fluid paths includesplural, discrete parallel paths therethrough and a single tip forpuncturing said test tube closure.
 7. The invention as defined in claim1 wherein at least a portion of the inlet path is concentric with atleast a portion of said discharge path.
 8. The invention as defined inclaim 1 wherein said pressurizing means is a bellows.
 9. The inventionas defined in claim 1 wherein at least a portion of said discharge pathis arcuate and at least a portion of said delivery means is concentricwith at least a portion of said inlet path.
 10. The invention as definedin claim 1 wherein at least a portion of said discharge path iscoextensive with at least a portion of said inlet path.
 11. Theinvention as defined in claim 1 wherein said means for establishing saidfluid paths includes two spaced apart, hollow cannulas.
 12. Theinvention as defined in claim 1 wherein said means for establishing saidfluid paths includes a generally thin, flat, blade-like portion.
 13. Theinvention as defined in claim 1 wherein said means for establishing saidfluid paths includes two spaced apart, hollow bores.
 14. The inventionas defined in claim 1 wherein said means for establishing said fluidpaths includes means for resisting removal from said closure.
 15. Theinvention as defined in claim 1 wherein said means for establishing saidfluid paths includes locator means for limiting the extent of insertionof the apparatus thereby facilitating automatic loading of a pluralityof fluid path establishing means in a plurality of test tubes. 16.Apparatus for transferring fluid from a test tube having an interiorsealed by a resilient, self-sealing, reusable, repuncturable closure atone end, said apparatus comprising:means for puncturing said resilient,self-sealing, reusable closure and for establishing a fluid inlet pathand a fluid discharge path, said fluid discharge path having an insidediameter; means for delivering fluid, said fluid delivering means havingan outside diameter and extending through said fluid discharge path;means for pressurizing the interior of the test tube for dischargingfluid contents through said delivery means; and a clearance beingdefined between said outside diameter of said fluid delivering means andsaid inside diameter of said fluid discharge path for venting theinterior of the test tube, said clearance being configured forpreventing accidental discharge of the fluid contents of the test tubewhen the test tube is subjected to temperature variations, saidclearance maintaining sufficient resistance to venting for pressurizingthe interior of the test tube for discharging the contents of the testtube when the interior is pressurized by said pressurizing means.